Drinkard et al. U.S. Pat. No. 3,538,142 disclose a process for isomerizing 3-pentenenitrile to 4-pentenenitrile using nickel hydride coordination compounds prepared from zero valent nickel complexes and an acid.
Schneider et al. U.S. Pat. No. 4,527,815 disclose the preparation of 4-pentenoates by the isomerization at elevated temperatures of 3-pentenoates using an acidic ion-exchange resin or acidic zeolite containing a noble metal of group 8 of the periodic table as a catalyst.
Hoeldrich et al. German Preliminary Published Application DE 3521 380 A1 disclose the synthesis of 4-pentenoic acid methyl ester by contacting 3-pentenoic acid methyl ester with Y zeolites containing cobalt in a +2 oxidation state and an alkali or alkaline earth metal.
The isomerization of methyl-3-pentenoate to methyl-4-pentenoate at elevated temperature using a pentasil zeolite without a metal promoter is also disclosed by Hoeldrich et al. in German Preliminary Published Application DE No. 3521 381 A1.
In pending U.S. application Ser. No. 48,651 the preparation of 4-pentenoates by isomerization of 3-pentenoates with perfluorinated ion-exchange catalysts is described. Pending U.S. application Ser. No. 57,433 describes the isomerization of 3-pentenenitriles to 4-pentenenitriles with heterogeneous catalysts containing noble metals of group 8 of the periodic table.